Automatic firearm



Dec. 12, 1939. H, VOLLMER 2,182,907

AUTCMATI C FIREARM Filed May 31, 1958 /nventorz Hemr'ch Vollmer'.

Patented Dec. 12, 1939 I acronimo c Application my 31, 193s, senti No. 211,049

In May 3l, 193? 2 This A known method of regulating the oi discharge oi automatic firearms consists in providing the weapon with a pneumatic brake which can be put into operation solas to retard the movement oi some reciprocating part of the rearm operative in connection with the disciprocating part oi the rearm mechanism so that the plunger retards the movement preceding the discharge of a shot, the pawl being, however, automatically disengaged from the reciprocating part when the required retardation 20 has been eecteci.

For rendering the brake'mechanism inoperative, so that the rate of discharge is normal, the ,pawl may be put out of operation by means of a manually controlled catch which prevents- -it from engaging the reciprocating member referred to.

The brake mechanism may be a detachable.

unit which can be fixed to the weapon by al simple operation, with the pawl in position to enao gage the reciprocating member. l

An embodiment of the invention is shown byl wg gf example in the accompanying drawing, in w c Fig. 1 is aside view, with a. portion of the as stock removed.

Fig. 2 being a plan view of the brake mechanism, in the operative position, and

Y Fig. 3 a plan view of the same in the inoperative position. w 4 and 5 are end views of the mechanism,

Fig. 6 is a section on the line A-B -of Fig. 4. Fig. 1 shows part of the stock l and trigger guard 2, and the clasp 3 holding the rear end 45 of the barrel tube-4 or chamber. The cartridge feed casing 5 has at the rear a narrow lug'B.

Between the stock I and`the cartridge feedcasing 5 is a brake cylinder 1, which has two cheeks 8, 8 fitting against the under part of the 5o barrel' tube 4. This part of the barrel has a Y recess 32 for entrance of one arm of a pawl I0 adapted to coact with a reciprocatingpart of the rearm. This may be the chamber 30, but where the barrel reciprocates it may be the barrel or a tubeflxed thereto. In the embodiment im. Me-3) `illustrated the chamber 3@ sliding in the tube d has at the bottom a recess 'ci' or an abutment for engagement with the pawl. The cylinder l hasat the rear two Alugs ii, ybetween which the lug 6 of the casing 5 engages. '5

'Ihe lugs have holes enabling the cylinder to be Ahired to the rearm by means of bolts i2, no

other fastening being required.

The axis of the cylinder i is slightly inclined to that ofthe tube fl, and the cylinder has therei@ in a plunger i3 urged rearwards by a coiled spring ifi. The cylinder is closed at the rear by a head l5, which is screwed into it and has vent` holes i@ and also a central hole for the plunger rod il. The cylinder head at the other end E@ has a small vent hole lil, the eective size of which may be regulatable.

Between the cheeks d and d the wall of the cylinder has an external guide channel i9 for a slide mwhich has an arm 2i xed by a nut g@ 22 to the plunger rod. The slide has a recess in which the pawl I0 is mounted on a pivot 2d, and a spring 25 acts on the pawl so that the tip of the pawl is urged out ofthe recess. and

the tail |01 of the pawl is pressed against the 25 bottom of the recess (Fig. 6).

When recoil causes the chamber to slide to the rear the pawl is rst depressed and the recess or abutment at the under part thereof then engages the pawl, so that when the chamber moves forwards again the slide 20 and plunger it move with it, th'e movement of the chamber being braked by the plunger. Owing to the inclined position of the cylinder the pawl recedes from the chamber during this movement, and is thereby at a certain point automaticallydisengaged therefrom, allowing the chamber to continue its movement, without brake action, for completing its part of the action which produces discharge. y 40 The cheek 9 has a slotted guideway for a slide having a handle 27 on the outside of the cheek and a nose 28 on the inside. The pawl it has a pin 28 projecting laterally therefrom into the path of the nose '28, so that when the handle 45 is pulled to the rear, into the position shown in A Fig. 3 the nose engages overV the pin and depresses the pawl, so that the pawlfcannot engage the chamber. A projection 281 on the nose limits the extent towhich the slide can be pulled l back. With the handle in the position shown in Fig. 2 the pawl is thrust out of the recess 18 by the spring 25, as shown in Fig. 6.

What I claim. as myinvention and desire to secure by Letters 'Patent'of the United States is: 55

1. An automatic rearm having in combination'ring mechanism including a member making a reciprocating movement operative for each discharge, a pneumatic brake comprising a cyl- 5 inder and' plunger therein. and a pawl connected to. said plunger, adapted temporarily to engage said reciprocating member during the movement of said reciprocating member preceding each discharge, so that brake action is applied'to said 2. An automatic firearm having in combina- .tion ring mechanism including a member making a reciprocating movement operative for each discharge, a pneumatic brake comprising a cylinder and a, plunger therein, said plunger having a rod projecting vfrom said cylinder, a slide slidable on said cylinder, parallel with the vaxis thereof, means connecting said slide -to said plunger rod, for reciprocating said slide, and a pawl mounted on said slide, adapted temporarily to engage said reciprocating member of said ilring mechanism during the movement of said reciprocating member preceding each discharge. so that brake action is applied to said movement by said plunger.

HEINRICH vom n 

